.TH "SRC/ztrexc.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*-
.ad l
.nh
.SH NAME
SRC/ztrexc.f
.SH SYNOPSIS
.br
.PP
.SS "Functions/Subroutines"

.in +1c
.ti -1c
.RI "subroutine \fBztrexc\fP (compq, n, t, ldt, q, ldq, ifst, ilst, info)"
.br
.RI "\fBZTREXC\fP "
.in -1c
.SH "Function/Subroutine Documentation"
.PP 
.SS "subroutine ztrexc (character compq, integer n, complex*16, dimension( ldt, * ) t, integer ldt, complex*16, dimension( ldq, * ) q, integer ldq, integer ifst, integer ilst, integer info)"

.PP
\fBZTREXC\fP  
.PP
\fBPurpose:\fP
.RS 4

.PP
.nf
 ZTREXC reorders the Schur factorization of a complex matrix
 A = Q*T*Q**H, so that the diagonal element of T with row index IFST
 is moved to row ILST\&.

 The Schur form T is reordered by a unitary similarity transformation
 Z**H*T*Z, and optionally the matrix Q of Schur vectors is updated by
 postmultiplying it with Z\&.
.fi
.PP
 
.RE
.PP
\fBParameters\fP
.RS 4
\fICOMPQ\fP 
.PP
.nf
          COMPQ is CHARACTER*1
          = 'V':  update the matrix Q of Schur vectors;
          = 'N':  do not update Q\&.
.fi
.PP
.br
\fIN\fP 
.PP
.nf
          N is INTEGER
          The order of the matrix T\&. N >= 0\&.
          If N == 0 arguments ILST and IFST may be any value\&.
.fi
.PP
.br
\fIT\fP 
.PP
.nf
          T is COMPLEX*16 array, dimension (LDT,N)
          On entry, the upper triangular matrix T\&.
          On exit, the reordered upper triangular matrix\&.
.fi
.PP
.br
\fILDT\fP 
.PP
.nf
          LDT is INTEGER
          The leading dimension of the array T\&. LDT >= max(1,N)\&.
.fi
.PP
.br
\fIQ\fP 
.PP
.nf
          Q is COMPLEX*16 array, dimension (LDQ,N)
          On entry, if COMPQ = 'V', the matrix Q of Schur vectors\&.
          On exit, if COMPQ = 'V', Q has been postmultiplied by the
          unitary transformation matrix Z which reorders T\&.
          If COMPQ = 'N', Q is not referenced\&.
.fi
.PP
.br
\fILDQ\fP 
.PP
.nf
          LDQ is INTEGER
          The leading dimension of the array Q\&.  LDQ >= 1, and if
          COMPQ = 'V', LDQ >= max(1,N)\&.
.fi
.PP
.br
\fIIFST\fP 
.PP
.nf
          IFST is INTEGER
.fi
.PP
.br
\fIILST\fP 
.PP
.nf
          ILST is INTEGER

          Specify the reordering of the diagonal elements of T:
          The element with row index IFST is moved to row ILST by a
          sequence of transpositions between adjacent elements\&.
          1 <= IFST <= N; 1 <= ILST <= N\&.
.fi
.PP
.br
\fIINFO\fP 
.PP
.nf
          INFO is INTEGER
          = 0:  successful exit
          < 0:  if INFO = -i, the i-th argument had an illegal value
.fi
.PP
 
.RE
.PP
\fBAuthor\fP
.RS 4
Univ\&. of Tennessee 
.PP
Univ\&. of California Berkeley 
.PP
Univ\&. of Colorado Denver 
.PP
NAG Ltd\&. 
.RE
.PP

.PP
Definition at line \fB125\fP of file \fBztrexc\&.f\fP\&.
.SH "Author"
.PP 
Generated automatically by Doxygen for LAPACK from the source code\&.